The immunocompetence of cancer patients referred for curative radiotherapy will be determined before and after treatment by their skin reactivity to 2-4 dinitrochlorobenzene (DNCB) and dilute croton oil and in vitro, lymphocyte response to phytohemagglutinin (PHA) stimulation as measured by H3 thymidine uptake. A correlation will be made between their immunocompetence as determined by these tests and the clinical stage of the disease, the histological type, and grade of the tumor, its rate of regression during treatment (radiation response), the local control rate and long term prognosis. Conversion after treatment from immunoincompetence to positive reactivity will be studied to determine if it is associated with a favorable prognosis.